Rational Design of Transition Metal-Phosphorus Dual-Atom Catalysts in Defective h-BN for CO₂ Hydrogenation and...

Dual-atom catalysts (DACs) have emerged as a promising platform for converting CO₂ into valuable chemicals, addressing critical energy and environmental challenges. Here, we theoretically designed M₁-P₁/V_BN catalysts by embedding single transition metal (M = Ir, Rh, and Co) and phosphorus atoms into defective h-BN. Extensive first-principles calculations were employed to investigate the mechanisms of CO₂ thermal hydrogenation to HCOOH and CO₂ cycloaddition with propylene oxide (PO) to produce propylene carbonate (PC). The metal-phosphorus dual-active sites were predicted to facilitate simultaneous activation and adsorption of CO₂, H₂, and PO, enabling detailed exploration of the reaction pathways. By combining static electronic structure calculations and microkinetic simulations, this work demonstrates that M₁-P₁/V_BN sheets show excellent catalytic performance for both reactions under relatively mild conditions, particularly for CO₂ hydrogenation on Co₁-P₁/V_BN and cycloaddition on Rh₁-P₁/V_BN. Stability analysis confirms the robustness of transition-metal-doped M₁-P₁/V_BN systems. Notably, the binding strength of small molecules strongly correlates with metal type, and a strong linear correlation was observed between the adsorption free energies of reactive intermediates. This study offers valuable theoretical insights into the thermocatalytic mechanisms of CO₂ hydrogenation and cycloaddition mediated by M₁-P₁/V_BN catalysts, laying a foundation for designing multifunctional DACs to advance CO₂ utilization technologies.